OpenSubdiv/opensubdiv/osd/glslTransformFeedbackKernel.glsl
2015-04-10 15:34:04 -07:00

107 lines
3.1 KiB
GLSL

//
// Copyright 2013 Pixar
//
// Licensed under the Apache License, Version 2.0 (the "Apache License")
// with the following modification; you may not use this file except in
// compliance with the Apache License and the following modification to it:
// Section 6. Trademarks. is deleted and replaced with:
//
// 6. Trademarks. This License does not grant permission to use the trade
// names, trademarks, service marks, or product names of the Licensor
// and its affiliates, except as required to comply with Section 4(c) of
// the License and to reproduce the content of the NOTICE file.
//
// You may obtain a copy of the Apache License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the Apache License with the above modification is
// distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the Apache License for the specific
// language governing permissions and limitations under the Apache License.
//
//------------------------------------------------------------------------------
uniform samplerBuffer vertexBuffer;
out float outVertexBuffer[LENGTH];
uniform usamplerBuffer sizes;
uniform isamplerBuffer offsets;
uniform isamplerBuffer indices;
uniform samplerBuffer weights;
uniform int batchStart = 0;
uniform int batchEnd = 0;
uniform int primvarOffset = 0;
//------------------------------------------------------------------------------
struct Vertex {
float vertexData[LENGTH];
};
void clear(out Vertex v) {
for (int i = 0; i < LENGTH; i++) {
v.vertexData[i] = 0;
}
}
void addWithWeight(inout Vertex v, Vertex src, float weight) {
for(int j = 0; j < LENGTH; j++) {
v.vertexData[j] += weight * src.vertexData[j];
}
}
Vertex readVertex(int index) {
Vertex v;
int vertexIndex = primvarOffset + index * STRIDE;
for(int j = 0; j < LENGTH; j++) {
v.vertexData[j] = texelFetch(vertexBuffer, vertexIndex+j).x;
}
return v;
}
void copyVertex(out Vertex dst, int index) {
for(int i = 0; i < LENGTH; i++) {
dst.vertexData[i] = texelFetch(vertexBuffer, index*STRIDE+i).x;
}
}
void writeVertex(Vertex v) {
for(int i = 0; i < LENGTH; i++) {
outVertexBuffer[i] = v.vertexData[i];
}
}
//------------------------------------------------------------------------------
void main() {
int current = gl_VertexID + batchStart;
if (current>=batchEnd) {
return;
}
Vertex dst;
clear(dst);
int offset = texelFetch(offsets, current).x;
uint size = texelFetch(sizes, current).x;
for (int i=0; i<size; ++i) {
int index = texelFetch(indices, offset+i).x;
float weight = texelFetch(weights, offset+i).x;
addWithWeight(dst, readVertex( index ), weight);
}
// the vertex buffer contains our control vertices at the beginning: don't
// stomp on those !
writeVertex(dst);
}
//------------------------------------------------------------------------------